The present invention relates generally to a method for the purification of exhaust gas of internal combustion engines and more particularly to an apparatus for significantly reducing the amount of incompletely burned fuel that is discharged from the exhaust system of an internal combustion engine to the atmosphere, thereby increasing the said engines fuel economy.
The exhaust gases which are emitted from present day automotive vehicles using unleaded gasoline consist primarily of unburned hydrocarbons (HC), carbon monoxide (CO), carbon dioxide (CO2), other natural by-products of combustion and nitrogen oxides (NOx). The CO gas when inhaled by humans combine with their blood cells and prevents them from conveying the oxygen (O2) content of air to their lungs, causing breathing problems. The HC and NOx constituents combine in the presence of heat and sunlight as they escape into the atmosphere to form Ozone (smog). Inhalation of Ozone has been documented to cause lung cancer. However, leaded gasoline operated automobiles also emit lead particles which causes lead poisoning if ingested by humans. Whereas, the diesel operated automobiles are known to emit micron size, carbon particles and sulfur dioxide/trioxide gases. The carbon particles are embedded in the human lungs, if inhaled and are known to cause lung cancer. The sulfur and nitrogen oxide gases are dissolved in rainwater to create acid rain which have devastated some forest lands through out the world.
Additionally, recent research has established that carbon dioxide (CO2)xcx9cthe main exhaust gas component although not a pollutant gas has been proven to be a green house gas (GHG). These gases are trapped in the lower atmosphere and prevent the radiation of solar heat from the earth""s heated surface to the atmosphere thereby causing Global Warming. For reducing this warming, it is of paramount importance to reduce the generation of GHG or carbon dioxide gases by the conservation of fuel/energy in all types of internal combustion engines, which currently use about one-quarter of our national petroleum consumption.
For the protection of our environment, the US Clean Air Act, 1970 stipulated the maximum emissions permissible for the various pollutant gases from new cars as under:
HC=0.41 gram/mile, CO=4.0 grams/mile, NOx=1.0 gram/mile. These values were to be observed in a Cold Start, Dynamometer Test run per the 1975 CVSII FTP. There was no requirement for in-use car tests or permissible reduced standards. However, twenty years later, the US EPA observed the progressive degradation of the air quality of the one hundred largest U.S. cities to below the mandated limits of the said Act. The cause for this degradation was traced to the failure of the Catalytic Converter Systemxcx9cthe sole automobile emission control system available ever since 1974xcx9cby the deposit of lead particles on the platinum catalyst from the small quantity of lead in today""s blend of the xe2x80x9clead freexe2x80x9d (unleaded ) gasoline. The non-methane HC gas conversion efficiency as a function of lead concentration on the catalyst of a three-way catalytic converter degrades from 100% to 48% with 0.01% xcx9c10% by weight of lead deposited on the catalyst: Reference: xe2x80x9cInternal Combustion Engine Fundamentalsxe2x80x9d, Dr. John B. Heywood, Prof. Mech. Engineering, Massachusetts Institute of Technology, 1988, FIG. 11-55. McGraw Hill Publications.
Similar degradation of the OEM catalytic converter has been recorded in the Federally-sponsored, xe2x80x9cReliability and Lifecycle Testing of The Automobile, Anti-Air Pollution and Energy Conservation System, hereafter referred to as the Bose System.xe2x80x9d US D.O.E Report, March 1980. During the U.S.D.O.E dynamometer controlled, 50,000 miles lifecycle tests with the Bose System, the OEM catalytic converter was tested at 1,134 miles (Test #1) and 12,140 miles (Test #2), before the removal of the converter and installation of the Bose Experimental System. The emissions control (grams/mile of the pollutant gases) and gravimetric fuel rates (m.p.g.) as recorded for Test #1(new converter), Test #2 (converter at 12140 miles), Test #9 (Bose System at 32,500 miles) and Test #12 (Bose System at 49.000 miles) are shown below
The emissions control efficiency recorded for the Bose Experimental System was constant at 30% of the new converter efficiency. However, the new converter""s efficiency dropped from 100% to 66% at 1,134 miles, 25% at 12,140 miles and a projected 5% at he end of its 50,000 miles"" service life. A lifecycle pollutant emissions study based on these test data has estimated that the lifecycle pollutant emissions for the catalytic converter is 2,621,488 grams as compared to the Bose System""s emissions of 900,000 grams. The Bose System""s fuel economy based on the converter""s fuel consumption was 6.7% in city driving and 19% in highway driving conditions.
Extensive road tests made with the preliminary prototypes of the Bose System on cars operating with leaded fuels in 1973, showed that the System was functional. The System separated the pollutant gases along with lead particles, from the fully burned carbon dioxide gases which were allowed to escape to the atmosphere. However, it was observed that the smaller lead particles were emitted along with the lighter pollutant gases via the turbine hollow shaft and slight accumulation in the mixing chamber contaminating its sodium hydroxide solution. Also, very large lead particles were observed to be exiting from the outlet pipe of the second stage separation""s gas collector chamber, which were being deposited in the mixing chamber, with much heavier contamination of the sodium hydroxide scrubber solution.
The creation of these unusually large lead particles was traced to the xe2x80x9cagglomeration of particlesxe2x80x9d phenomenon observed on the inside surface of the said gas collector chamber, caused by the particles high speed, hot impact at 90 degrees angle of incidence with subsequent re-boundings. Such rebound impacts created a xe2x80x9cscoringxe2x80x9d and roughness on the gas collector inside surfaces, whereon larger particles were noticed to grow before being dislodged. This adverse phenomenon required frequent scrub down of the gas collector inside surfaces and needed further research for overcoming these xe2x80x9cagglomerationxe2x80x9d problems. Fortunately, by Mar. 4, 1974xcx9cthe filing date of my prior Art: U.S. Pat. No. #3,861,142xcx9cthe Federal/State laws had been promulgated for the exclusive sale of unleaded gasoline through out USA. Also, I lacked the funds needed to carry out the said research. This research has been done during the last few yearsxcx9cparticularly, as the demand for the micronsize carbon particles separation/re-combustion from the diesel operated, internal combustion engines exhaust, have become critical from the point of view of health and fuel/energy conservation. My present invention describes the new technology developed for reducing the xe2x80x9cagglomeration of particlesxe2x80x9d problem that makes the Bose System universally interchangeable between the internal combustion engines operated by leaded or unleaded or diesel or natural gas fuels respectively.
Most previously used processes for separating gases of dissimilar molecular masses, and, or lead or carbon particles generally have required complex and expensive equipment, and additionally must be carefully controlled in order to effect the desired separation. Other devices suffer from serious disadvantages, such as, generally requiring the application of external energy for speeding up the gas to gas or gas to particle separation.
Examples cited are: U.S. Pat. Nos. 4,622,051; 4,649,703; 4,989408. These three processes depend upon the use of high voltage field for the electrostatic precipitation of the micron size carbon particles in the diesel exhaust to create larger particles build-up on the cyclone chamber walls, for their easier removal during the subsequent centrifugal separation process. Thus, the xe2x80x9cparticle agglomerationxe2x80x9d effect is being promoted in these patents, in spite of loss of external electrical energy and the potential heat loss from the smaller micron- size, carbon particles lost in the xe2x80x9cagglomerationxe2x80x9d process. Thus, U.S. Pat. No. 6,176,889 B1 requires a rotating impeller to provide centrifugal effect to the contaminated gas flow. Similarly, U.S. Pat. No. 6,200,361B1 needs high air velocity to operate system and is cumbersome for automotive use. U.S. Pat. No. 3,815,337 comprises a cylindrical cyclone chamber with circumferential slots which discharge carbon particles into an xe2x80x9cagglomerationxe2x80x9d chamber packed with wire mesh to catch these particles. This system is bound to give significant pressure drop and does not re-cycle the separated carbon particles and will thus be very energy in-efficient.
All or some of the listed factors in the penultimate paragraph, together result in an impractical size from the standpoint of space requirements for automotive uses. Examples cited are: U.S. Pat. Nos: 2,789,032; 3,793,807; 3,918,937; and 2,954,841; 3,712,029; 5,053,063. In U.S. Pat. No. 5,053,063, SISK uses polymer or xe2x80x9cTeflonxe2x80x9d tubes for collecting dust particles in a xe2x80x9cDust Filtering and Collection Systemxe2x80x9d by allowing passage of the dust laden air stream through the micron size pores of the tubes, and relies mainly on one characteristic of the polymer or xe2x80x9cTeflonxe2x80x9d tubes, namely low friction to enable the drop off of particles collecting on tube sides. Sisk also uses vibrating means to dislodge adhering particles. Whereas, my present invention uses an industrial low-friction, as well as, high-temperature and abrasionxe2x80x94resistant coating, which are two very important characteristics relied upon by me, in selecting from a plurality of thermosetting and inorganic coatings, including TEFLON or Porcelain Enamels, in order to successfully solve the said adverse xe2x80x9cagglomeration of particlesxe2x80x9d phenomenon discovered with my present invention. Thus, in the light of U.S. Pat. No. 5,053,063 by SISK, my present invention is not obvious.
In brief description of my prior Art: U.S. Pat. Nos: 4,399,107; 4,235,845; 3,892,070 ; 3,861,142 and Canadian Patent No: 1,104,060 shows and claims the basic combination of turbine impeller and conical vortex tube. Thus, an engine exhaust effects the rotation of a turbine impeller which increases the speed of exhaust gas passing there through into the conical vortex tube, wherein the whirling gas mass is centrifugally stratified into a core of lighter unburned combustible gases fed back from the larger end of the vortex tube to the engine via a mixing chamber containing a water/sodium hydroxide charge that dissolves out the pollutant gases, such as formaldehyde and nitric oxide, while an outer layer of heavier gas exhausts at the smaller end to the atmosphere.
U.S. Pat. No. 3,861,142 improves the combination in salvaging from the component of heavier gas outer layer certain separated heavier gas component and fed back to the engine, passing through a mixing chamber containing a water/chemical charge that removes by dissolving the pollutants such as acetaldehydes and nitrogen oxides. A final portion comprising lighter non-combustible components of the heavier gas layer passes to exhaust at the smaller end of the vortex tube.
U.S. Pat. No. 3,861,142 effects gas separation in two stages instead of the single stage shown in U.S. Pat. No. 3,892,070. Both teachings use a turbine impeller having dimensions based on a six-cylinder engine (Ford Fairlane, 1965, 200 c.i.d) as noted in U.S. Pat. No. 3,861,142.
U.S. Pat. No. 4,235,845 and Canadian Patent No: 1,1 04,060 improved the arrangement of the vortex separation. This patent also effects improvements over the teachings of my prior patents. Thus, it was found that an increase in the number of blades on the turbine impeller to a multiple of twice the number of cylinders e.g., for an eight cylinder car to sixteen blades on the impeller increased the velocity energy of the exhaust gases in the vortex tube by an increase in the energy conversion efficiency of the turbine. A stator wheel upstream of the turbine impeller with gas entry to the stator wheel reduces turbulence, and more importantly, a stator wheel downstream of the turbine impeller overcomes a slow down of the turbine as seen in tests at about 1300 rpm in at least two different automobiles, i.e. six and eight cylinder engines. It was discovered that this was due to the exit gas from the impeller, when going into the vortex tube, was actually spinning in a reverse direction from the rotational direction of the impeller, which resulted in a reduction of the separated lighter gas components. The advantage of this simple expedient of a downstream stator wheel was a significant improvement in the amount of lighter combustible and pollutant gases separated.
U.S. Pat. No. 4,399,107 improved the wet chemical chambers for the purification of the separated lighter and heavier pollutants by their combination into a compact, integral body for positioning ease under the hood of existing automobiles.
Among the several objects and advantages of the present invention may be noted:
the prevention of atmospheric pollution by carbon monoxide, unburned hydrocarbons, nitrogen oxides, sulfur oxides, aldehydes, lead and carbon particles heretofore emitted in substantial proportions from the exhaust gases of internal combustion engines, and principally such engines of the type powering automotive vehicles;
the provision of a new and improved apparatus for separating the different gaseous and particle components constituting the exhaust gas emission from automotive vehicle-type internal combustion engines for the purpose of appreciably reducing the proportion of harmful and, or pollutant gases/particles being present in such gases which are emitted into the atmosphere;
the provision of an improved apparatus for separating gases/particles in a gas/particle mixture having different molecular weights/densities, which is compact, continuously operative, inherently reliable and may be simply and inexpensively manufactured and retrofitted to all existing and in-use automotive vehicles;
the provision of a novel and improved apparatus which may be universally applied for separating the combustible gases/particles from the noncombustible gases/particles in the exhaust gas being emitted from any type of solid, liquid or gas burner and which increases the thermal efficiency of the same by permitting the return of the combustible gases/particles to the burner for subsequent re-combustion.
In accordance with the teachings of the present invention, it has been found that the foregoing objects and their attendant advantages can be realized with a conventional internal combustion engine, such as is used in automotive vehicles, by providing an anti-exhaust gas pollution and thermal regenerative device having no moving parts and which, when connected to the exhaust or tailpipe of such vehicles, operates automatically to substantially separate the heavier incombustible or fully burned, components from the lighter combustible, or only partially burned components of the exhaust gas, and recycles the lighter, unburned components, causing the same to be directed back into the air-intake of the engine for further or complete combustion.
This device simply comprises an elongate converging, vortex tube which terminates in a small discharge outlet at one end and fitted with a down-stream stator wheel, at its large junction end with the cylindrical housing of the turbine impeller and immediately adjacent to the impeller. A suitable support for the impeller is provided on a hollow axial rotary shaft, extending up to the large end of the vortex tube and exteriorly of the cylindrical housing carried on high temperature/high speed ball bearings, within the cylindrical housing, the outer end of which is fashioned into an annular chamber for the circulation of the bearing""s cooling water from the engine""s radiator. An upstream stator wheel is mounted to the inside of the cylindrical housing of the turbine impeller and immediately ahead of it. An inlet pipe is arranged and disposed near the closed, wall end of the cylindrical turbine housing for discharging the exhaust gases from the engine tangentially, or peripherally therein.
As the engine exhaust gas is introduced through the inlet pipe, it is directed through the upstream stator wheel for reducing the gas turbulence before its impact on the turbine impeller blades. The expansion of the gas through the turbine blades causes the turbine to speedup considerably, which increases the speed of the exhaust gas mass passing there through into the downstream stator wheel and into the conical vortex tube, wherein the convoluting gas mass is centrifugally stratified into three layers, in accordance with their molecular weights: the inner core comprises of the lighter combustible hydrocarbons and nitric oxide gases which are fed back through the hollow shaft of the gas turbine to the gas mixing chamber/sodium hydroxide scrubber, wherein the nitric oxide gases are dissolved out prior to their re-combustion in the engine; the middle layer comprises the non-combustible, fully burned carbon dioxide gases which exit to the atmosphere through the small end of vortex tube; the outermost layer comprises the heavier combustible hydrocarbon gases, non-combustible nitrogen dioxide gases, sulfur dioxide/trioxide gases, aldehydes , lead/carbon particles which are separated through elongated, radial slots milled at the smaller end of the vortex tube and collected in the second separation stage chamber, prior to their re-circulation to the engine after being treated through a plurality of air filter assemblies for the progressive removal of nitrogen dioxides, sulfur trioxides, aldehydes and lead particles.
The present invention teaches a new technology for reducing the xe2x80x9cagglomeration of lead/carbon particlesxe2x80x9d phenomenon by (a) milling the radial slots of vortex tube at a tilt angle 30 degrees to vertical, with the tilt conforming towards the exit pipe of said second separation stage chamber, (b) by applying an industrial coating to the said chamber""s inside surface selected from a plurality of a low-friction, high temperature, abrasion-resistant coatings. Additionally, the present invention teaches the use of a plurality of compressed air in-line filter assemblies as an improved apparatus than the chemical chambers of my prior Art, for removal of aldehydes, sulfur, sulfates, nitrogen dioxide, water vapor and lead/carbon particles from the separated and combustible, heavier hydrocarbon exhaust gas stream of the leaded gasoline/diesel engine exhaust, by their centrifugal dispersal and selective removal by the passage of the separated gases through the top stator vanes and porous elements of the said plurality of air filter assemblies.